Many of the known systems for ideographic composition suffer from one serious disadvantage which results in complicated and time consuming operation. The disadvantage resides in the nature and design of the character selection part of the system, commonly a keyboard. Because of the volume of characters constituting the vocabulary in such ideographic languages as Chinese, the use for such languages of the basic keyboard arrangement, employed for English and other European languages, in which each different character is assigned to a respective key of the keyboard, results in a single extremely large keyboard, or possibly in a set of alternative keyboards. Even in the latter arrangement, each keyboard includes a very large number of keys, the process of character selection by the keyboard operator involving searching through the large keyboard character vocabulary resulting in an undesirably long average character selection period.
Computer operated photocomposing systems are presently being developed, in which the data concerning character form is stored in an accessible store and is extracted therefrom in response to store address signals derived from keyboard operation. The computer can be programmed to carry out automatic justification and spacing of the characters produced in a suitable photocomposing machine supplied with the aforesaid data.
The continual advances made in computer technology have resulted in the provision of considerable data storage facilities such that in the field to which this invention relates, the storage of the information concerning the orthographic structure of the characters of an ideographic language is a relatively insignificant problem as compared with that of character selection. Clearly this is because it is improbable that, in the foreseeable future, the human element will be entirely eliminated from the process of sequential selection of the characters. Where, as in composition in English or some other European language, the process of character selection is related to a small character alphabet, the dependence of this process upon human visual and intellectual functions represents a very minor problem in terms of efficiency, as measured in, for example, words per minute, as compared with ideographic languages employing vast alphabets of ideographic characters (roughly equivalent to "words" in English).
On the other hand, once the process of character selection has been carried out, the subsequent processes of signal generation, data retrieval, character justification spacing and formation can all proceed automatically under the direction of computer programme without human intervention and the attendant limitations concerning speed of operation.
It would therefore be advantageous to provide a system in general, and a keyboard in particular, adapted to improve the character selection rate and to facilitate the application of computer operated photocomposition to ideographic languages.
All of the more common Oriental ideographic languages e.g. Chinese, Japanese, Korean possess a common feature, viz. most of the characters of any such language can be constructed from a respective set of basic character components, or so-called modified radicals. As used herein a character component is a basic character element which may or may not have both linguistic and orthographic identity (by this it is meant that it may or may not have a meaning of its own in the linguistic sense and be visually represented alone in the orthographic sense) but which can form part of one or more composite characters comprising different geometrical arrangements of such character components. This construction of characters from relatively simple components is a well-known characteristic of ideographic languages and accordingly will not be discussed in greater detail herein.
It has therefore become clear during the course of the inventor's research into the possibility of improving the character selection facility in equipment requiring manual operation to achieve sequential character selection, that a keyboard having very much fewer keys than in known systems where each full ideographic character is assigned to a respective key, could provide the selection facility if instead the keys had these character components assigned to them. An operator having knowledge of, say Chinese, and able, (as any reasonably literate Chinese person would be) to decompose notionally a Chinese character into its constituent components could operate such a keyboard by depressing the selected keys in the order on which the associated components would be written when writing the character by hand. For each Chinese character, this order is laid down by recognised orthographic rules and can therefore be employed as part of the basis for a system for responding to the operation of the selected keys to identify uniquely the character constituted by the character components associated with those keys.